The objective of this paper is to discuss the role the Landless Workers Movement (MST) has played in helping eleven women, who have participated in the author's research, construct their identities as activist educators. The MST, one of the largest and most important social movements in contemporary Latin America, has struggled for agrarian reform as well as social and economic justice in Brazil. Education is also a quite important dimension of the MST's struggles. This paper reveals, therefore, the complex mechanisms of the construction of an identity as activist educator and some of the main experiences in the landless movement that have made the development of this type of identity possible among the participants in this research. Jlio Diniz' major professional interests focus on sociology of curriculum and teacher education, in general, and, more specifically, on critical theory and teacher education for cultural diversity and social justice. He received his Ph.D. in 2004 from the University of Wisconsin-Madison in Curriculum and Instruction. Professor Diniz is the Editor of a Book Series called Docncia (Teaching) at Autentica Publisher in Belo Horizonte, Brazil. He is also the Editor of Formao Docente ' Revista Brasileira de Pesquisa sobre Formao de Professores (Brazilian Journal of Research on Teacher Education).